Wheel cover



Mmh 1, 1960 G. A. QON 2,926,956

WHEEL COVER Filed July 22, 1955 2 Sheets-Sheet 1 EZQS G. A. LYON WHEELCOVER March l, 1960 Filed July 22, 1955 2 Sheets-Sheet 2 United StatesPatent p WHEEL covEn. George Albert Lyon, Detroit, Mieli.ApplicationJuly 22,1955,4 Serial No. 523,747 16,. claims. (ci. salsn Thepresent invention relatesato improvements in wheel structures andf moreparticularly concerns the ornamental and protective covering of theouter sides of vehicle wheels.-

With the advent` of thetubeless tire, it is desirable to provide-meanson the terminal flanges of the vehicle wheelsto facilitate workingthereover of the fairly stii beads of the tires in mounting or removingthe same. I- have proposed that this beaccomplishedby providing thetirelrim with a modified lterminal ange construction wherein the-extremity oftheterminal flangeis provided with an additional width or extension thatisA directedto` a substantial width radiallyinwardly for thereby"providingA a smooth round, substantiallyabrasionand-sharpedgefree`surface over which the beads ofthe tires` can bewo1ked-without unduefriction and without dangenof abradingi` or'cutting the surfaceofthe-bead.

Since-this proposed construction provides a` substantially U-shaped`inwardly opening channel in the terminal flange; I now further proposethat such grooveorI channel be utilized for the reception of coverretaining meansby which wheel covers for the outer sides ofthe wheelsare adapted-` to beV retained on the wheel;

It is accordingly anA important object of the present' inventionV toprovide an improved wheel structure` including novel means for retainingwheel covers.` thereon.

Another object of the invention is to provide anl improved wheelstructure including a novel cover and` coverv retaining "combination,

A further object of the invention is to provideirnproved means forVretaining wheel covers onvehicle wheels.

It is yet another object of the invention to` providev novel coverretaining clip means by which wheel covers are adapted to be held insnap-on, pry-off relation on vehicle wheels.

A` still further object ofthe invention is to provide improved wheelcover means for disposition` at the. outer side of vehicle wheels.

`O ther objects, features and'advantages of the present* invention willbe readily. apparent from the following detailed description of certainpreferred embodiments thereof taken, in conjunction with theaccompanyingY drawings, in which: p p

Figure l isA an outer side elevational view of ay vehicle wheelstructure embodying features of' the invention;` i

with certain'part brokenaway to show detail of structure;

Figure?. is anA enlarged fragmentaryfradial sectionalf view taken'substantially on the line IIf--II ofFg. 1;

FigureV 3 is a fragmentary radial sectionali view sub-- stantially likeFig," 2` but showing a' slightmoditication;

i The present `invention isA4 especiallyv concerned with'. a..

turned smooth resilient thrusting shoulder extremity 29- which` inassembly bottomsrsiidably against the terminal bottoming,thrusting;extremityishoulderportion 29 assister` vehicle wheel suchas anautomobile wheel of the kind that isA particularlyy suitable forsupporting a tubeless tire 10,' although it may be used-With a -tii'eand tube combination if desired. The tire 10 is supported by amulti-llange, drop-center tire rim which includes an in ner base flange11 that is secured inA suitable manner to an attachment ilange 12 of adisk spider Wheel body 13. From the outer side of the base flange 11extends a side flange 14 that is adapted to support a suitable valvestern 15. At the radially outer side of the side llange 1,4` it mergeswith an intermediate generally axially outl wardly and' radiallyoutwardly sloping ilange 17 that leads into a terminal llange 18directed generally radially outwardly therefrom and then turnedgenerally axially outwardly as shown at` 19.

At its outer extremity the'terminal llange is provided with a generallyradially inwardly extending annular flange lip extension 20 ofsubstantial width affording at the juncture ofthe tlange extension 20`with the preferably arcuately curved, both circumferentially andtransversely, axially extending portion 19 a rounded smooth shoulder 21.Within the terminal flange is thus provided a generally radiallyinwardly opening annular channel or groove 22 providing a substantialchamber or socket.

According to the presentinvention the groove chamber or socket 22' isutilized for the reception therein of cover retainingv means preferablyin the form of retaining spring clips 23 of which'theremay be as many aspreferred, but are shown as four in number in Fig. 1. Each ofthe clips23V is Vpreferably formedfrom suitable resilient sheetrnetal stoclcsuchas spring steel, or the like, and is constructed and arranged to` beself-retaining' within the socket '22. To` this end,` the spring clip 23includes a` body 2d` of substantial width and of a length that ispreferablyjlonger than the terminal eX- tension ange 2li but notinexcess oflthe width of the inner radially extending portion 18 `of theterminal lan'ge structure., p

At one end portiony thereof the body 24 ofthe clip is provided' with aretaininghead comprising a shoulder 25. arrangedtto bottom or seatwithin the groove socket 22. and preferably curved or contoured`complementary thereto at least in a longitudinal cross-sectional sense.Spacedifrom the body 24 and turned'divergently relativeth'ereto is aretaining terminal' llange 27 at the ex-V tremity ofthe head 25. Thetipofthe retaining terminal`27 normally projects'` to a greater width ordistance from the body 24`than the space between the terminal flangeportions` 18"and 20. retaining clipV 23 longitudinally into the groovesocket 22', the resilient retaining terminal 27 is placedundercompression and thus is resiliently tensioned and the tip thereofthrusts bitingly against the terminal llange portion `'land is thusmaintained by the backed-up relation of the body 24 against the terminalflange extension 20.`

Since the terminal retaining flange 27 of the clip is angled radiallyand axially inwardly, any tendency for provided.witharesilient coverretaining shoulder. portion,

28 that'is exposedl radially inwardly. from` the terminal llangeextremity portion 2t)-v and in thisinstance comprises a radiallyinwardly convex portionvhaving an underllange portion 18 adjacent tojuncture thereof with the intermediate tlange 17. Throughithisarrangement'the Hence, upon pressing, the

in maintaining the clip in assembly with the tire rim ilange sincenormally the thrusting shoulder portion 29 extends to a greater Iwidthor spacing relative to the body 24 than the spacing between the terminalange portions 18 and 20. However, the thrust shoulder extremity portion29 is radially slidable on the terminal tlange portion 18 in response toradially outward thrust against the cover retaining shoulder 28 andresilient radially outward deection thereof, which develops a resilienttension tending at all times to return the shoulder 28 radially inwardlyto its normal position.

By the provision of the retaining clips 23 a wheel cover 30 is adaptedto be retained in snap-on, pry-olf relation on the outer side of thewheel. In the present instance the cover 30 is shown as comprising asheet metal disk that substantially covers the Wheel body 13 and thetire rim and is of the full disk type, although the cover may, ifpreferred, comprise a trim ring arrangement, that is an annulus thatcovers only the tire rim or the tire rim and an adjacent portion of thewheel body. In any event, the cover 30 may be made from suitable sheetmaterial such as stainless steel, brass, aluminum alloy, or the likeadapted to be made by suitable manufacturing techniques such as stampingor drawing, and then appropriate finish such as polishing and plating.

In its radially outer portion, the wheel cover 30 has an annulargenerally radially and axially outwardly projecting area 31 that isarranged to overlie the outer side of the tire rim and more particularlythe side flange 14 thereof. This joins on a juncture rib-like annularreinforcing ridge 32 with a radially outer annular portion 33 of adiameter slightly less than the diameter at the tip of the terminalflange extremity 20. Behind the marginal cover portion 33 is anunderturned annular flange 34 providing at its juncture a reinforcingand finishing bead 35 and in the present instance adapted to seat inassembly against the radially inwardly extending exposed portion of theclip body 24.

For snap-on, pry-ofir cover retaining interengagement with the coverretaining resilient shoulder structure 28 of the clips, the underturnedilange 34 is provided with a cover retaining flange extension 36directed substantially axially inwardly on a diameter that is adapted toaccommodate the clip shoulders radially outwardly thereof when aterminal extremity retaining shoulder structure 37, herein in the formof an outturned continuous annular bead 37 engages with the radially andaxially inwardly facing portion of the resilient retaining shoulder 28.Herein, the spacing between the axially inner extremity of the retainingbead 27 and the clip engaging shoulder portion of the underturned ilange34 is such that when the ilange 34 is seated against the clips, the bead37 will be supported inl spaced relation to the tire rim. Thereby thecover is entirely supported by the retaining clips in resilient,cushioned relation both against radial and axial deilectional forces.

In applying the cover 30 to the outer side of the wheel7 the retainingbead 37 is seated against the axially outer side of the shoulder 28 ofthe retaining clips and axially inward pressure applied to the outerside of the cover to press the bead 37 against the radially inwardlyprojecting underlying portions of the retaining clips to effectresilient compression and radially outward deection of the retainingclip shoulder until the beads 37 snapbehind the clip shoulders. At thesame time, of course, the underturned flange portion 35 comes to rest orbottoms or seats against the retaining clips which thus support thecover in predetermined axial disposition relative to the wheel, whereinthe outer marginal portion 33 of the cover is preferably supportedapproximately in the plane of the turned terminal ange extremity portion20 so as to be protected by the terminal flange against curbing or otherobjects toward which the wheel may be driven.

Since the retaining clip shoulders 28 are placed under substantialresilient tension as a result of engagement thereof by the retainingmeans on the shoulder, a irm retaining gripping interengagement of theretaining clip shoulders and the retaining bead 37 of the cover ismaintained.

Removal of the cover from the wheel may be effected by inserting apry-off tool such as a screw driver between the outer bead 35 and thetip of the terminal ange extremity portion and then by the applicationof pryoi force the retaining bead 37 of the cover can be snapped freefrom the retaining clip shoulders 28.

In Fig. 3 a slightly modied arrangement is shown wherein the wheel 'andthe retaining clips are preferably substantially the same as inthe formof Fig., 2 and are therefore identiied in all particulars by the samereference numerals. In addition, the cover is preferably substantiallythe same as the cover 30 and is thus identified by similar referencenumerals, except that a retaining ange 36' as an axially inwardextension from the underturned flange 34 is provided that is somewhatlonger than the similar cover flange 36 in Fig. 2. Accordingly, when thecover of Fig. 3 is applied to the outer side of the wheel, and theretaining terminal bead 37 is snapped behind the clip retainingshoulders 28, the retaining bead 37 will engage against the tire rim andmore particularly adjacent juncture of the intermediate flange 17 withthe terminal ilange portion 18 to thereby determine the axialdisposition of the cover, while the underturned cover iiange 34 will bemaintained in spaced relation to the clips.

Having reference to the form of the invention shown in Fig. 4, a cover40 is adapted to be applied to the outer side of a vehicle wheel whichin all essential respects may be the same as the wheel shown in Fig. 2and is therefore similarly identitied as to the several parts. In thisform the wheel cover 40 has a generally radially and axially outwardlyextending annular portion 41 that joins on an annular reinforcingrib-like ridge 42 an outer annular marginal cover portion 43 which inthe present instance is directed generally radially outwardly andaxially inwardly and terminates in an underturned reinforcing and coverretaining annular bead 44 adapted to interengage with retaining springclips 45 which may be of suitable number and constructed and arranged toengage retainingly within the annular groove socket 22 of the tire rim.

Each of the retaining clips 45 includes an elongated body 47 ofsubstantial width adapted to engage against the inner side of theterminal frange extremity portion 20 and has at its radially outer end aturned shoulder 48'that engages within the base of the groove 22 andterminates in a generally radially and axially inwardly directed clipretaining biting edge or end terminal 49 that engages bitingly underresilient tensioned thrust against the opposing surface of the terminalflange por tion 18, similarly as the terminal 27 of the clips 23.

At its radially inner end portion the clip body 47 is provided withcover retaining means that extends radially inwardly beyond the edge ofthe terminal flange portion 20. Herein such retaining means comprises asocket arrangement for receiving and resilientlyv retaining andsupporting the cover bead 44. To this end, a generally axially inwardlydirected ange portion 50 is provided as an extension from the clip body47 and has a turned generally radially inwardly vand axially outwardlydirected and axially outwardly opening socket` portion 51 receptive ofthe cover bead 44 and terminating in a generally axially outwardlyextending and radially inwardly turned resilient retaining terminal ange52. Both the socket ange extension 50 and the retaining resilientterminal ange 52 are preferably provided with overhanging respectiveshoulders that engage about the bead at the axially outer side thereof,so that the bead retaining socket 51 actually engages the bead over morethan of its surface axially outwardly beyond a radial plane through thecenter of the bead. Through outer; side of the-fwheelf is adapted` tobe.l effected;V by,

aligningthe bead44 thereof Withthe axially Aoutwardlyopeningcoverretaining sockets 51` of the retaining clips Vtainingsocket51. of, the clips.

Inthe form ofthe invention shown, in Fig, 5, a wheel coverf55 is`adapted` .to beapplied to` theouter side` of` a vehicle.wheel structurethat is in all essential respects the same as that shown in Fig. 2 andaccordingly similar reference numerals identify similar parts` thereofexcept that;l the` terminal flange` extremity is,` as shown at 2liVturned generally radially and axially inwardly obliquely so. that.` themouth. of the socket groove 22k is slightly narrower than the`maximurnwidth of the groove ad-` jacent` the bottom, thereof.

t Withinthe narrow-mouth4 groove 22 in Fig. 5, is-sup-' porteda seriesof retainingfspringclips 5,7, ofsuitable number, lcircumferentiallyspaced, adapted foi-'retaining thecover 5S in snap-om pryol relation onthe. wheel. 'Ilothis end, eachof the clips-.57 includes a longitudinalbody 58'of substantial width having Va, head end portion 59.that isgenerally complementary to and seats within tl'lev groove `22 and,terminates in a generally radially. and axially inwardly, obliqueresilient retaining terminal Harige 60 that engages at.itstip `in bitingretaining relation with the opposing surface of the terminal flangeportion18. The clip body, of course, engages against the inner surfaceofthe terminal ilange extension 2li and.A at its radially inner endportion projects beyond the tip-of the flange extremity. v

For retaining the cover 55 on thewheel, the clips 58 are each providedwith a radially inner end cover-retain ing socketportion 61 whichcomprises a terminal flange on, the body 58 that extends generallyaxially inwardly and ,then is turned radially inwardly and is adapted toseat under resilient` tension` against the tire rim adjacent juncture ofthe intermediate iiangev 17 with the terminal ange portion 18. Itwill beobserved that the axially extending portion of the socket terminalflange 61 oliV the clip has an overhanging shoulderlthat is retaininglyengageable overa terminal annular bead 63 of the-cover extremity attheedge of a generallyradially outwardly and axially inwardly directedmarginal portion 64 of the cover. Such marginal portion `is joined by arib-like ridge 65 annularly about a generally radially and axiallyoutwardly directed cover portion 67 on the cover plate 55.

I'n` applying the cover 55 tothe outer side of the wheel, it isgenerally centered with respect to` the wheel andv then the terminalbead163 of the cover is pressed axially inwardly to snap behind theslightly smaller diameter' shoulder 62 ofthe retaining clips into nestedengagement within the socket flange 61 of the clips which not onlyretains the bead 63 but thereby supports thecover.4 At thetsame time, ofcourse, the retaining socket ange 61 of the clips is placed underradially outward thrusting resilient compression by the cover bead 63which is resisted by the: clip body 58 which thus establishes'aresiliently-tensioned engagement of the cover` bythe clips.

like may be-applied behindthe terminal-beadV63` ofthe covenand,xthenfulcrumed; againstthe tip of the tire For: removing the cover 55fromthe wheel, a pry-off tool such` as a screwdriver or the.

Y retaining clips.

It willV beappreciated,` of course, that,` eachVv of the coversl40 and4S mayfbemade from similar material 1 andaccording to similar process asdescribed fortthe cover 30.

Inieach of the wheel, structures described, after `the respective coversare mounted on the wheel, the retaining outer marginal portionsofV thecoversengage interlock-` ingly with the respective retaining clips tothereby posi-` tively hold the clips withinthe socket of the tirerim.terminal ange against` any possibility of` working out` of4 such socketin service. However, even after` the cover is,- removed, theclips willbe` effectively retained within the terminal flange sockets by theexpanded. resilient biting tip retaining terminalflanges at theretaining headend. portions of the clips andthe clips maybe removed onlyby deliberately prying the terminal retaining flanges thereof freefromthe terminal flange of thettire rim by. meansof asuitable tool. l

It will be understood that modiiicationsand variations may be eifectedwithout departing from the scope of` the novel concepts of `therpresent,invention.

IV claim as my invention:

l. In a Wheel structure including a tire v.rim` having a generallyradially inwardly opening groove therein, a retaining clip retaininglyAengaging, in said groove, the

clip `having a radially inner resilient cover retaningtangef portion,and a cover for disposition at the outer side of the wheel having an`outer marginali portion including,

a terminal extremity retainingly engageableiwith thezrefn taining clipretaining flange portion in snap-on, pry-off, relation, said terminal`extremity including aA pair` of` shoulders gripping the retaining`flange portion of` the: retaining clip therebetween.

2. ln a wheel structure` including a tirerim having a` generallyradially inwardly opening groove therein,4 a,

retaining clip retainingly engaging in said groove, the clip having aradially inner resilient cover retaining flange portion, and a coverforl dispositionV at the outer side.of the wheel having an outermarginal portion includinga terminal extremity retainingly engageablewith the retaining clip retaining .ilange portion in snapon, pry-olf`relation, said terminal extremity of the cover beingv engageable withand shouldering against the tire -rirn behind' the resilient retainingflange of the clip.

3. In a wheel structure including a tire rim having;

wall portions and a base portion connecting said walls in a generallyLJ-sllaped` structure, a cover retaining clip for,4 engagement Withinsaid groove including ,'axiallyl spaced resilientlyspreadable portionsretainingly engage ably thrusting against the-opposing surfaces ofsaidwall` portionsinside said groove and, joined by-a head portion opposingsaid base portion of the groove, witha cover; retaining opposite endportion ofv the clip projecting from the groove.

5. In a wheel structure including a generally radially;

opening annular groove having axially inner and'outerr wall portions anda base portion connectingr said walls,

a cover retaining clip for engagementwithin saidgroove-i` includingresiliently spreadable portions retainingly en-` gageably thrustingagainst said wall portions andjoined;y by a head portion opposing said.base` portiongof.. the,

groove, with a" cover retaining opposite end` Portionen,

the clip, said opposite end vportieri of the clip comprising a turnedunder resilient cover retaining shoulder flange, said turned undershoulder flange bottoming resiliently against the tire rirn and therebyapplying thrust against the remainder of the clip to assist in holdingthe clip in said groove. j

6. In a wheel structure including a tire rim having a terminal flangeprovided with a flange extremity extension to define within the terminalflange a generally U- shaped annular radially inwardly opening socketgroove, a plurality of cover retaining clips mounted within said grooveincluding fingers extending generally radially inwardly and axially forbiting wedging engagement with a wall of the groove, and said clipshaving portions thereof extending from the groove for retainingengagement with a cover to Vhold the cover on the wheel.

7. In a wheel structure including a tire rim having a terminal flangeprovided with a flange extremity extension to define within the terminalflange a generally U- shaped annular radially inwardly opening socketgroove, a plurality of cover retaining clips mounted within said grooveand having portions thereof providing extensions extending therefrom forretaining engagement with a cover to hold the cover on the wheel, saidcover retaining extensions including a turned under resilient flangethrusting resiliently against the tire rim.

8. In a wheel structure including a tire rim having a terminal flangeprovided with a flange extremity extension to define within the terminalflange a generally U- shaped annular radially inwardly opening socketgroove, a plurality of cover retaining clips mounted within said grooveand having portions thereof providing extensions extending therefrom forretaining engagement with a cover to hold the cover on the wheel, saidcover retaining extensions including a generally radially inwardlyopening socket for engagement with a bead on the cover.

9. In a wheel structure including a tire rim having a substantiallyU-shaped terminal flange with a generally radially inwardly openingsocket groove therein defined by a lip terminal portion projectingsubstantially radially inwardly, retaining clipshaving radially outerterminal portions thereof housed and engaged within said socket grooveand having portions thereof projecting radially inwardly out of saidgroove beyond said lip terminal and turned for providing cover retainingshoulders adjacent to the edge of said lip terminal, and a cover fordisposition at the outer side of the wheel having means thereon adjacentto the mouth of the groove and retainingly interengageable with saidshoulders of the clips.

l0. In a wheel structure including a tire rim having a substantiallyU-shaped terminal flange with a generally radially inwardly openingsocket groove therein defined by a lip terminal portion projectingsubstantially radially inwardly, retaining clips having radially outerterminal portions thereof housed and engaged within said socket grooveand having portions thereof projecting radially inwardly out of saidgroove beyond said lip terminal and turned for providing cover retainingshoulders adjacent to the edge of said lip terminal, and a cover fordisposition at the outer side of the wheel having means thereon adjacentto the mouth of the groove and retainingly interengageable with saidshoulders of the clips, said clip shoulders supporting the cover out ofengagement with the wheel.

11. In a wheel structure including a tire rim having a substantiallyU-shaped terminal flange with a generally radially inwardly openingsocket groove therein defined by a lip terminal portion projectingsubstantially radially inwardly, retaining clips having radially outerterminal portions thereof housed and engaged within said socket grooveand having portions thereof projecting radially inwardly out of saidgroove beyond said lip terminal and turned for providing cover retainingshoulders adjacent to the edge of said lip terminal, and a cover fordisposition at the outer side of the wheel having means thereon adjacentto the mouth-of the groove and retainingly interengageable with saidshoulders of the clips, said retaining clip shoulders includingresilient flanges bottomed against the tire rim.

12. `In a wheel structure including a tire rim having a substantiallyU-shaped terminal flange with a generally radially inwardly openingsocket groove therein dened by a lip terminal portion projectingsubstantially radially inwardly, retaining clips having radially outerterminal portions thereof housed and engaged within said socket grooveand having portions thereof projecting radially inwardly out of saidgroove beyond said lip terminal and turned for providing cover retainingshoulders adjacent to the edge of said lip terminal, and a cover fordisposition at the outer side of the wheel having means thereon adjacentto the mouth of the groove and retainingly interengageable with saidshoulders of the clips, said retaining means o'n the cover including aturned substantially stiff terminal bead engageable with the retainingclip shoulders.

13. In a wheel structure including a tire rim having a terminal flangewith an extremity extension directed generally radially inwardly intooverlying relation to the tire rim, said extension being disposedgenerally obliquely axially inwardly toward its tip and defining withthe remainder of the terminal flange a groove that has an opening thatis narrower at the tip of said extension than the remainder of thegroove, and cover retaining clips having radially outer portions thereofsupported and retained within said remainder of the groove and radiallyinner portions projecting from said opening for retaining engagementwith a portion of a cover.

14. In a wheel structure including a tire rim having on the Outer sidethereof a terminal flange including a generally radially extendingportion joining an intermediate flange and having at the radially outermargin thereof a generally axially outwardly turned portion, coverretaining clips carried by the terminal flange and having resilientradially deilectable retaining shoulder portions facing generallyradially inwardly and including adjacent additional generally axiallyinwardly facing shoulder means slidably bottoming on said radiallyextending terminal flange portio'n adjacent to juncture thereof with theintermediate flange, and a cover for disposition over the outer side ofthe wheel including an outer marginal cover retaining terminal structureengageable in press-on, pry-off relation with said radially facingshoulder portions, said axially inwardly facing shoulder means on theclips retaining the shoulder portions of the clips in predeterminedaxially inward disposition during the presson of the cover.

15 In a wheel structure including a tire rim having on the outer sidethereof a terminal flange including a generally radially extendingportion joining an intermediate flange and having at the radially outermargin thereof a generally axially outwardly turned portion, coverretaining clips carried by the terminal flange and having resilientradially deflectable retaining shoulder portions facing generallyradially inwardly and including adjacent additional generally axiallyinwardly facing shoulder means slidably bottoming on said radiallyextending terminal flange portion adjacent to juncture thereof with` theintermediate flange, and a cover for disposition over the o'uter side ofthe wheel including an outer marginal cover retaining terminal structureengageable in press-on,

pry-off relation with said radially facing shoulder pon4 tions, saidaxially inwardly facing shoulder means on the clips retaining theshoulder portions of the clips iny predetermined axially inwarddisposition during the press-on of the cover, said axially outwardlyturned terminal flange po'rtion including a generally radially inwardlyextending terminal lip portion overlying the first mentioned radiallyextending terminal flange portion" and coasting with the retaining clipsto retain the same against axially outward displacement during pry-oi ofthe cover.

16. In a wheel structure including an annular portion providing a socketgroove of substantial depth with an annular mouth opening generallyradially therefrom, a resilient sheet metal cover-retaining clipselectively mounted within the circumference defined by said socketgroove and substantially enclosed therein, said clip having on theportion thereof'within the sooket groove retaining means grippinglyinterengaging with the Walls of the socket groove and thereby heldtherein, the clip having as the only exposed portion thereof coverretaining means projecting a limited distance from the mouth of thesocket groove for resilient press-on., pry-olf retaining engagement withretaining means on a cover.

References Cited in the file of this patent UNITED STATES PATENTS2,649,566 Knapp Aug. 4, 1936 2,123,025 Ramirez July 5, 1938 2,148,995Nelson Feb. 28, 1939 2,351,655 Aske June 20, 1944 2,419,174 Lyon Oct.29, 1946 2,440,858 Hollerith May 4, 1948 2,749,184 Wood June 5, 1956

